Structure–properties‐performance relationships in complex epoxy nanocomposites: A complete picture applying chemorheological and thermo‐mechanical kinetic analyses

Abstract

Herein the kinetics of network formation (cross‐linking) and network degradation (thermal decomposition) in a complex system based on epoxy resin reinforced with hyperbranched amino polymer‐functionalized nanoparticles (HAPF) were discussed. Five classes of nanoparticles, that is, nano‐SiO2, halloysite nanotubes (HNTs), HNTs@nano‐SiO2 core/shell, HAPF/nano‐SiO2, HAPF/HNTs@nano‐SiO2 core/shell were loaded at 0.5, 1.0, 2.0 (optimal loading among prepared samples), and 5 wt% were examined. Parameters of the cure kinetics and degradation were correlated, and the mechanical properties were interpreted in terms of microstructure and rheological analyses. The isothermal chemorheological cure kinetics study (60, 70, and 80°C) revealed a low activation energy for epoxy/HAPF/HNTs@nano‐SiO2 core/shell nanocomposite (72.21 kJ/mol), compared with the blank epoxy (79.99 kJ/mol). Correspondingly, gel time of the system decreased from 1040 to 515 to 237 s upon isotherms of 60, 70, and 80°C, respectively. Tensile strength was also increased vividly (ca. 32%), possibly due to the strong interfacial adhesion, which reflected in an induced shear yielding. Nitrogen‐mediated thermal decomposition kinetics suggested an average degradation activation energies of ca. 150 and 210 kJ/mol for the assigned nanocomposites and the blank epoxy, respectively. Overall, there was a complete agreement between the kinetics of network formation and network degradation in the studied epoxy nanocomposite. This work enables understanding of structure‐properties‐performance in complex epoxy nanocomposites.

Design and characterization of high‐performance epoxy adhesive with block copolymer and alumina nanoparticles in aluminum‐aluminum bonded joints: Mechanical properties, lap shear strength, and thermal stability

“…The prepared molds were removed after 24 h and the dog-bone specimens and metal-to-metal single-lap joint samples were left at room temperature for 7 and 2 days, respectively, for the purpose of final curing. [2,19] ] The designed formulations used for fabricating the dogbone and single-lap joint samples are reported in Tables 1 and 2. Table 2 shows the single-lap joint samples that had the best results in the tensile test (Table 1).…”

“…Epoxy resins have found many applications in fiberreinforced composites, which are used as matrix and adhesive in the construction, automotive, aerospace industries, and so forth. [1,2] Cured epoxies are amorphous with a high-degree of crosslinking. This microstructure leads to some advantageous properties such as a high modulus, limited shrinkage, and high performance at elevated temperatures, which are favorable in engineering applications.…”

Addressing diffusion behavior and impact in an epoxy–amine cure system using molecular dynamics simulations

“…Network formation and molecular structure of epoxy systems are determined by crosslinking reactions, which limit the diffusion of molecules 17 . Therefore, understanding the detailed kinetics of crosslinking is a key to manufacturing high-performance composites for special demands and applications, such as mechanically strong structures 18 – 23 .…”

Effect of fumed silica and halloysite nanoparticles on the microstructure, mechanical, and fracture properties of thermoplastic polyolefin elastomer toughened polypropylene

“…Furthermore, this comparison between these nanoparticles was also reported by a few researchers. For example, Jouyandeh et al [ 26 ] showed the tensile modulus of epoxy/FS systems was more than epoxy/HNT ones at varying levels of nanoparticles.…”

“…[21][22][23][24][25] Few authors studied the effects of FS and HNT in polymers, comparatively. Jouyandeh et al [26] studied the impact of HNT and FS on the mechanical properties of epoxy systems. They reported that the tensile strength for epoxy/FS systems was more than epoxy/HNT ones.…”